In collaboration, AMRA Medical and Fulcrum Therapeutics created a standardized whole-body magnetic resonance imaging (MRI) protocol to evaluate skeletal muscle composition in patients with facioscapulohumeral dystrophy (FSHD) – a slowly progressing muscular dystrophy. An abstract describing this work was accepted and made publicly available by the Muscular Dystrophy Association.

Clinical trial investigators commonly use functional tests such as the 6-Minute Walk Test and single-slice MRI to evaluate neuromuscular disease progression. These techniques can vary substantially, creating unwanted data noise – potentially making trials larger, longer and more costly. Additionally, there is a lack of standards for implementing whole-body MRI in multi-center trials, making it challenging to quantify how the disease affects individual muscles throughout the body in different stages of the disease. Lastly, neuromuscular disease studies often emphasize only the legs. This study includes whole muscle volumes in the legs, trunk, shoulders, and arms.

AMRA and Fulcrum conducted a study to evaluate, optimize and standardize a whole-body MRI protocol for use in clinical trials for Fulcrum’s losmapimod – a small molecule investigational therapeutic for FSHD. Together, they successfully developed a detailed musculoskeletal MRI protocol to quantify muscle fat fraction, lean muscle volume, and muscle fat infiltration. They volumetrically and bilaterally analyzed 18 individual muscles in 16 adults with FSHD across 6 clinical sites using diverse MRI scanner manufacturers. Fulcrum recognizes that AMRA’s technology is a significant advancement in neuromuscular clinical trials and plans to use this protocol as part of the further development of losmapimod.

Diego Cadavid, Fulcrum Therapeutics’ Senior Vice President of Clinical Development says, “Commonly used endpoints – such as functional tests – have limitations, so we engaged with AMRA based on their ability to reliably and quickly segment and quantify muscles. Together we developed an MRI protocol that generates stable images from which AMRA's algorithms produce consistent, quality, objective and reproducible biomarkers that we now use in our ongoing clinical trial program.”

This study further demonstrates that AMRA’s MRI technology: 1) has the potential to follow heterogeneous disease distribution; 2) is compatible with major MRI scanner manufacturers, making multicenter trials more feasible; 3) can perform whole-body 3D volumetric measurements of individual muscles and muscle groups, enabling earlier and more accurate detection of fat and muscle changes; and 4) can longitudinally monitor several different muscles specific to the neuromuscular disorder and patient.

These results rationalize the exploration and use of AMRA’s methods in additional neuromuscular clinical trials. The full abstract for Development and Evaluation of a Whole-Body MRI Imaging Protocol And Analysis Algorithms to Measure Changes in Skeletal Muscle in FSHD (#142) can be viewed on the MDA 2020 website.